1. Technical Field
The present invention relates to a driving method of an electrophoretic display device.
2. Related Art
In this type of electrophoretic display device, in regard to each of a plurality of pixels, an image is displayed by moving the electrophoretic particles through application of a driving voltage to, for example, an electrophoretic layer including white and black electrophoretic particles interposed between a pixel electrode and a common electrode. Additionally, by changing the period of time when the driving voltage is applied to the electrophoretic layer for each pixel, halftone (for example, gray) is displayed.
On the other hand, as this type of electrophoretic display device, there is an electrophoretic display device provided with a pixel circuit (a so-called 1T1C pixel circuit) configured to include one TFT (thin film transistor) which functions as a pixel switching element and one condenser which functions as a memory circuit (namely, a holding capacitor).
For example, in JP-A-2007-79170, a technology is disclosed for preventing an uneven display of color in a case of switching between display colors in an electrophoretic display device, by changing the application time of a driving voltage in accordance with the continuous display time of a display color displayed before switching.
In this type of electrophoretic display device, when displaying halftone, there is a technical problem in that there is a concern that noise may be generated in the displayed image. Namely, even if the same driving voltage is applied to display the same halftone in different pixels, there are cases where different halftones are displayed depending on the pixel. A difference in halftone such as this which is actually displayed by two pixels which are to display the same halftone is visually recognized as image noise. In a case where halftone is displayed, there is a tendency that noise is more notably generated as the duration of the driving voltage applied to display halftone becomes shorter. The cause is not clear but, for example, in an electrophoretic display device with a 1T1C pixel circuit as described above, manufacturing variations in the condenser included in each pixel circuit (in other words, differences in condenser characteristics between condensers provided for each pixel) are considered to be one of the causes.